I'm a little late to the party, but anyway.
Using your phone or cheap mic will make your video sound cheap, even if you filmed it in 4k. If you use a decent mic, you can "pass" even if you film with a low res camera.
I know it's not the case, because most phones film at super high resolution these days, but the point was to show that a decent mic is very important.
Without getting into too much detail, I'd recommend you to limit your search to condenser mics.
Another thing to think about is the connection. XLR connections require audio interfaces (which is another expense) while USB mics connect right into your computer.
SM57B gets many recommendations every time this type of question arises. I love this mic, I have 3 of them, but I'd never use it for video because it's a dynamic mic, and for it to sound good you'll have to have it in the frame (which is not an issue for voiceover, but still limiting in terms of movement).
It also requires an audio interface, so it's 0/2.
Blue Yeti is a very nice one you can have for about $75, and the Nano version is also great at about $50. I never owned any of them, but I heard unedited audio recordings of both and they are very nice. Just make sure you get the USB version.